CN117631285A

CN117631285A - Optical system and head-mounted device

Info

Publication number: CN117631285A
Application number: CN202211156206.4A
Authority: CN
Inventors: 黄日忠; 洪于杰
Original assignee: Dagen Optical Industry Co ltd
Current assignee: Dagen Optical Industry Co ltd
Priority date: 2022-08-19
Filing date: 2022-09-22
Publication date: 2024-03-01
Also published as: EP4325271A1; US11803062B1; TW202409638A

Abstract

The application discloses an optical system comprises an aperture, an image surface, a reflective polarizing element, a partial reflective element, a first quarter-wave plate, a second quarter-wave plate, a first optical lens, a second optical lens and a third optical lens. The aperture and the image plane are respectively positioned at the front side and the rear side of the optical system. The reflective polarizer is located between the aperture and the image plane. The partial reflecting element is positioned between the reflecting polarized light element and the image surface. The first quarter-wave plate is positioned between the reflective polarizing element and the partially reflective element. The second quarter wave plate is positioned between the partial reflecting element and the image surface. The first optical lens, the second optical lens and the third optical lens are sequentially positioned between the aperture and the image surface from the front side to the rear side. The first optical lens has negative refractive power. The front surface of the second optical lens is a plane. The application also discloses a headset with the optical system.

Description

Optical system and head-mounted device

Technical Field

The present disclosure relates to an optical system and a headset, and more particularly, to an optical system suitable for a headset.

Background

With the progress of semiconductor technology, various electronic devices have been miniaturized, so that the performance of the miniature electronic device is greatly improved compared with the prior art, the pixels of the photosensitive device can reach a smaller size, the development of the portable device is also vigorous, and the rapid progress of the lens device is driven, so that the head-mounted device only existing in the science fiction film in the past is also started to be raised. Meanwhile, the popularity of high-performance microprocessors and micro-displays has led to rapid advances in smart headsets in recent years. With the rise of artificial intelligence, the application range of electronic devices equipped with optical lenses is wider, wherein the demands for computer vision are greatly growing, and the demands for optical lenses are also more diversified.

In addition to the significant weight reduction of modern headsets, applications in fields such as Virtual Reality (VR), augmented Reality (Augmented Reality, AR), and Mixed Reality (MR) are rapidly growing. Wherein, virtual reality is widely used in medical care, engineering, real estate, education, game, video entertainment, etc. However, the present head-mounted device is still in development, and there are still many areas to be greatly improved, such as weight and volume of the head-mounted device, and imaging quality of the image. In the early days, most of the virtual reality headsets used conventional optical lenses or fresnel lenses, in which the conventional optical lenses can provide good imaging quality but cannot effectively compress the volume, while the fresnel lenses can achieve the effect of compressing the volume, but the imaging quality is often poor, so that the present researches or developers are searching for a lens combination with both small volume and good imaging mode.

Disclosure of Invention

In view of the above-mentioned problems, the present application discloses an optical system and a headset, which can have smaller weight and volume and better imaging quality.

The application provides an optical system, which comprises an aperture, an image surface, a reflective polarizing element, a partial reflective element, a first quarter-wave plate, a second quarter-wave plate, a first optical lens, a second optical lens and a third optical lens. The aperture is located on the front side of the optical system. The image surface is positioned at the rear side of the optical system. The reflective polarizer is located between the aperture and the image plane. The partial reflecting element is positioned between the reflecting polarized light element and the image surface. The first quarter-wave plate is positioned between the reflective polarizing element and the partially reflective element. The second quarter wave plate is positioned between the partial reflecting element and the image surface. The first optical lens is positioned between the aperture and the image surface. The second optical lens is positioned between the first optical lens and the image surface. The third optical lens is located between the second optical lens and the image surface. The first optical lens has negative refractive power, the third optical lens has positive refractive power, and the front surface of the second optical lens is a plane. The radius of curvature of the front side surface of the third optical lens is R5, and the radius of curvature of the rear side surface of the third optical lens is R6, which satisfies the following condition:

0.13<R6/R5。

The application further provides an optical system comprising an aperture, an image plane, a reflective polarizer, a partially reflective element, a first quarter-wave plate, a second quarter-wave plate, a first optical lens, a second optical lens and a third optical lens. The aperture is located on the front side of the optical system. The image surface is positioned at the rear side of the optical system. The reflective polarizer is located between the aperture and the image plane. The partial reflecting element is positioned between the reflecting polarized light element and the image surface. The first quarter-wave plate is positioned between the reflective polarizing element and the partially reflective element. The second quarter wave plate is positioned between the partial reflecting element and the image surface. The first optical lens is positioned between the aperture and the image surface. The second optical lens is positioned between the first optical lens and the image surface. The third optical lens is located between the second optical lens and the image surface. The first optical lens has negative refractive power, and the front side surface of the second optical lens is a plane. The radius of curvature of the front side surface of the first optical lens is R1, and the radius of curvature of the rear side surface of the first optical lens is R2, which satisfies the following condition:

|R2/R1|<1000。

the application provides a headset comprising the optical system.

According to the optical system and the head-mounted device disclosed by the application, the wave plate, the reflective polarizing element, the partial reflecting element and the lens are combined to convert the polarization state of imaging light, so that the imaging light can be reflected among the elements to form the catadioptric optical system, thereby compressing the optical path and reducing the generation of stray light, and further achieving the volume compression and weight reduction of the head-mounted device. In addition, the refractive optical system has the advantages that the first optical lens has negative refractive power, and the front side surface of the second optical lens is a plane, so that excellent imaging quality can be provided.

When the second optical lens front side surface is planar, the arrangement of the optical element is facilitated.

When the first optical lens has negative refractive power, the third optical lens has positive refractive power, and R6/R5 satisfies the above conditions, the imaging quality can be adjusted.

When the first optical lens has negative refractive power and |r2/r1| satisfies the above condition, it is helpful to adjust the imaging quality.

The foregoing description of the disclosure and the following description of embodiments are provided to illustrate and explain the spirit and principles of the present application and to provide a further explanation of the claims of the present application.

Drawings

Fig. 1 is a schematic diagram of an optical system and a display according to a first embodiment of the present application.

Fig. 2 shows an enlarged schematic view of the region EL1 in fig. 1.

FIG. 3 is a schematic diagram showing an aperture stop, a first optical lens, a second optical lens, a third optical lens, an image plane and imaging ray traces of different fields of view of the optical system of FIG. 1.

Fig. 4 is a schematic diagram of an optical system and a display according to a second embodiment of the present application.

Fig. 5 is a schematic diagram of an optical system and a display according to a third embodiment of the present application.

Fig. 6 is a schematic diagram of an optical system and a display according to a fourth embodiment of the present application.

Fig. 7 is a schematic diagram of an optical system and a display according to a fifth embodiment of the present application.

Fig. 8 is a schematic diagram of an optical system and a display according to a sixth embodiment of the present application.

Fig. 9 is a schematic diagram of an optical system and a display according to a seventh embodiment of the present application.

Fig. 10 is a schematic diagram of an optical system and a display according to an eighth embodiment of the present application.

Fig. 11 is a schematic diagram of an optical system and a display according to a ninth embodiment of the present application.

Fig. 12 is a schematic view of an optical system and a display according to a tenth embodiment of the present application.

Fig. 13 is a schematic view of an optical system and a display according to an eleventh embodiment of the present application.

Fig. 14 is a schematic view of an optical system and a display according to a twelfth embodiment of the present application.

Fig. 15 is a schematic view of an optical system and a display according to a thirteenth embodiment of the present application.

Fig. 16 is a schematic view of an optical system and a display according to a fourteenth embodiment of the present application.

Fig. 17 is a schematic view of a headset according to a fifteenth embodiment of the present application.

Fig. 18 shows a schematic top view of the headset of fig. 17.

Fig. 19 is a schematic diagram showing parameters ImgH, EPD, CT1, CT2, CT3, T12, T23, ER, TD, SL and inflection points of the rear surface of the first optical lens according to the first embodiment of the present application.

[ symbolic description ]

1,2,3,4,5,6,7,8,9,10,11,12,13,14 optical system

10 head-wearing device

101 display

102 digital signal processor

103 inertial measurement unit

104 support structure

105 eyeball tracking device

106 optical system

107 auto-focusing device

108 camera

109 folding mechanism

100 iris identification module

BS: partially reflecting element

CT1 center thickness of the first optical lens on the optical axis

CT2 center thickness of the second optical lens on the optical axis

CT3 center thickness of the third optical lens on the optical axis

E1 first optical lens

E2:second optical lens

E3 third optical lens

EL1 region

ER distance between aperture and front surface of first optical lens on optical axis

EPD size of aperture

EYP: position of eyes of user

ImgH, the image height presented by the image plane

IMG image plane

P point of inflection

QWP1 first quarter wave plate

QWP2 second quarter wave plate

RP (reflection type) polarized light element

ST: diaphragm

SC: display device

SL distance from aperture to image plane on optical axis

T12 distance on optical axis between rear side surface of first optical lens and front side surface of second optical lens

T23 distance on the optical axis from the rear surface of the second optical lens to the front surface of the third optical lens

TD, distance on optical axis from front side surface of first optical lens to rear side surface of third optical lens

Detailed Description

The detailed features and advantages of the present application are described in sufficient detail to enable those skilled in the art to practice the invention, and the related objects and advantages of the application are readily understood by those skilled in the art from the disclosure, claims, and drawings of the present application. The following examples further illustrate the aspects of the present application in detail, but do not limit the scope of the present application in any way.

The application provides an optical system, which preferably comprises an aperture, an image surface, a reflective polarizing element, a partial reflective element, a first quarter-wave plate, a second quarter-wave plate, a first optical lens, a second optical lens and a third optical lens. Preferably, the aperture is located at the front side of the optical system, and the image surface is located at the rear side of the optical system. The front side of the optical system refers to the side of the optical system, for example, near the eyes of a user, and the rear side of the optical system refers to the side of the optical system, which is near a display, for displaying an image, wherein the image surface can be located on the display, and the position of the aperture can be a position adjacent to the eyes of the user for viewing the image.

Preferably, the reflective polarizing element is located between the aperture and the image plane. Preferably, the partial reflecting element is located between the reflective polarizing element and the image surface. Preferably, the first quarter-wave plate is located between the reflective polarizing element and the partially reflective element. Preferably, the second quarter wave plate is located between the partial reflecting element and the image surface. Preferably, the first optical lens is located between the aperture and the image plane. Preferably, the second optical lens is located between the first optical lens and the image plane. Preferably, the third optical lens is located between the second optical lens and the image plane. Preferably, the first optical lens has negative refractive power, and the front surface of the second optical lens is a plane. Preferably, an air gap is provided between the first optical lens and the second optical lens. Preferably, an air gap is provided between the second optical lens and the third optical lens. Preferably, the partially reflective element may for example have an average light reflectivity of at least 35%, wherein the average light reflectivity may refer to an average value of the reflectivity of the partially reflective element for light rays of different wavelengths.

The optical system disclosed by the application converts the polarization state of imaging light through the combined configuration of the wave plate, the reflective polarizing element, the partial reflective element and the lens, so that the imaging light can be reflected among the elements to form the catadioptric optical system, thereby compressing the optical path and reducing the generation of stray light, providing excellent imaging quality and achieving the reduction of volume and weight of the head-mounted device. Furthermore, the feature that the front surface of the second optical lens is planar facilitates the arrangement of the optical elements. Preferably, the imaging light emitted from the image plane sequentially passes through the second quarter-wave plate, the partial reflection element, the first quarter-wave plate and the reflection type polarization element, so as to facilitate the correctness of light polarization, reflection and penetration through a specific imaging light path. In detail, referring to fig. 19, the imaging light is incident on the optical system 1 from the display SC in the longitudinal polarization state and is emitted from the image plane IMG, the rotation polarization state is formed by the second quarter-wave plate QWP2, the transverse polarization state is formed by the partial reflection element BS and then penetrating the first quarter-wave plate QWP1, and the reflective polarization element RP is only penetrated by the imaging light in the longitudinal polarization state, so that the imaging light in the transverse polarization state is reflected and penetrates the first quarter-wave plate QWP1 again to form the rotation polarization state, and then the imaging light in the rotation polarization state is reflected by the partial reflection element BS and then penetrates the first quarter-wave plate QWP1 for the third time to form the longitudinal polarization state and then can penetrate the reflective polarization element RP. Therefore, the required optical path can be folded through the reflection mode, and the length of the lens group is effectively shortened. Preferably, the first quarter wave plate, the second quarter wave plate and the partially reflecting element may be respectively plated (attached) on the surface of the lens or may be separate elements separated from the lens, respectively, which is not limited thereto. Preferably, the partially reflective element is, for example but not limited to, a mirror with a reflective surface, which is capable of reflecting a portion of the light. For example, in some cases, the partially reflective element may be configured to allow a portion of light to be transmitted and another portion to be reflected when light passes through.

The radius of curvature of the front side surface of the third optical lens is R5, and the radius of curvature of the rear side surface of the third optical lens is R6, which preferably satisfies the following condition: 0.13< R6/R5. Thereby, the imaging quality can be adjusted. Among them, the following conditions are also preferably satisfied: 0.15< R6/R5. Among them, the following conditions are also preferably satisfied: 0.25< R6/R5<1000. Among them, the following conditions are also preferably satisfied: 0.50< R6/R5<500. Among them, the following conditions are also preferably satisfied: 1.2< R6/R5. Among them, the following conditions are also preferably satisfied: 1.5< R6/R5. Among them, the following conditions are also preferably satisfied: 2.0< R6/R5<1000.

Preferably, the third optical lens element may have positive refractive power. Therefore, the first optical lens with negative refractive power is matched, and when R6/R5 meets the above conditions, the imaging quality can be further adjusted.

The radius of curvature of the front side surface of the first optical lens is R1, and the radius of curvature of the rear side surface of the first optical lens is R2, which preferably satisfies the following condition: R2/R1 <1000. Therefore, the negative refractive power of the first optical lens can be matched, and the imaging quality can be adjusted. Among them, the following conditions are also preferably satisfied: R2/R1 <500. Among them, the following conditions are also preferably satisfied: R2/R1 <100. Among them, the following conditions are also preferably satisfied: R2/R1 <50. Among them, the following conditions are also preferably satisfied: R2/R1 <10.

Preferably, at least one optical lens in the optical system has a inflection point; thereby helping to adjust the peripheral aberrations. Preferably, the rear surface of the first optical lens may have at least one inflection point; thereby helping to further adjust the peripheral aberration. Preferably, the rear surface of the third optical lens may have at least one inflection point; thereby helping to further adjust the peripheral aberration. Referring to fig. 19, a schematic diagram of an inflection point P of the rear surface of the first optical lens E1 according to the first embodiment of the present application is shown. Fig. 19 shows the inflection point P of the rear surface of the first optical lens E1 as an exemplary illustration in the first embodiment of the present application, but in the first embodiment and other embodiments of the present application, each lens may also have one or more inflection points.

The abbe number of the first optical lens is V1, the abbe number of the second optical lens is V2, the abbe number of the third optical lens is V3, the abbe number of the ith optical lens is Vi, the refractive index of the first optical lens is N1, the refractive index of the second optical lens is N2, the refractive index of the third optical lens is N3, the refractive index of the ith optical lens is Ni, and at least one optical lens in the optical system preferably satisfies the following conditions: 10< vi/Ni <50, where i=1, 2 or 3. Therefore, the situation that the refractive index difference is too large due to different angles under the condition of reflection of light rays can be avoided, and the imaging quality is further affected. Among them, the following conditions are also preferably satisfied: 12< vi/Ni <45, where i=1, 2 or 3. Among them, the following conditions are also preferably satisfied: 30< vi/Ni <40, where i=1, 2 or 3.

The focal length of the optical system is f, the image plane presents an image height of ImgH (which may be half of the total diagonal length of the display), which preferably satisfies the following conditions: 1.00< f/ImgH <1.50. Thus, a larger image can be provided. Among them, the following conditions are also preferably satisfied: 1.00< f/ImgH <1.25. Among them, the following conditions are also preferably satisfied: 1.05< f/ImgH <1.25. Referring to fig. 19, a schematic diagram of a parameter ImgH according to a first embodiment of the present application is shown.

The distance from the aperture to the image plane on the optical axis is SL, and the image plane presents an image height of ImgH, which preferably satisfies the following conditions: 1.2< SL/ImgH <2.0. Therefore, the image size and the optical system length can be balanced. Among them, the following conditions are also preferably satisfied: 1.45< SL/ImgH <1.90. Among them, the following conditions are also preferably satisfied: 1.50< SL/ImgH <1.80. Among them, the following conditions are also preferably satisfied: 1.55< SL/ImgH <1.80. Referring to fig. 19, a schematic diagram of parameters SL and ImgH according to a first embodiment of the present application is shown.

The distance from the aperture to the image surface on the optical axis is SL, and the focal length of the optical system is f, which preferably satisfies the following conditions: 1.2< SL/f <2.0. Therefore, the imaging quality and the length of the optical system can be balanced. Among them, the following conditions are also preferably satisfied: 1.25< SL/f <1.75. Among them, the following conditions are also preferably satisfied: 1.30< SL/f <1.70.

The distance from the aperture to the front surface of the first optical lens on the optical axis is ER, and the distance from the aperture to the image surface on the optical axis is SL, which preferably satisfies the following conditions: 0.30< ER/SL <0.50. Therefore, the dizzy degree of the user can be reduced. Among them, the following conditions are also preferably satisfied: 0.35< ER/SL <0.45. Referring to fig. 19, a schematic diagram of parameters ER and SL according to the first embodiment of the present application is shown.

The distance between the front surface of the first optical lens and the rear surface of the third optical lens on the optical axis is TD, and the distance between the aperture and the image surface on the optical axis is SL, which can preferably satisfy the following conditions: 0.40< TD/SL <0.60. Thereby helping to shorten the length of the lens group. Among them, the following conditions are also preferably satisfied: 0.42< TD/SL <0.58. Among them, the following conditions are also preferably satisfied: 0.45< TD/SL <0.58. Among them, the following conditions are also preferably satisfied: 0.45< TD/SL <0.55. Among them, the following conditions are also preferably satisfied: 0.50< TD/SL <0.55. Referring to fig. 19, a schematic diagram of parameters TD and SL according to the first embodiment of the present application is shown.

The first optical lens has a central thickness on the optical axis of CT1, the second optical lens has a central thickness on the optical axis of CT2, the third optical lens has a central thickness on the optical axis of CT3, the distance from the rear surface of the first optical lens to the front surface of the second optical lens has a distance on the optical axis of T12, and the distance from the rear surface of the second optical lens to the front surface of the third optical lens has a distance on the optical axis of T23, which preferably satisfies the following conditions: 1< (Ct1+Ct2+Ct3)/(T12+T23) <20. Therefore, the lens service efficiency is improved. Among them, the following conditions are also preferably satisfied: 2< (Ct1+Ct2+Ct3)/(T12+T23) <18. Among them, the following conditions are also preferably satisfied: 2< (Ct1+Ct2+Ct3)/(T12+T23) <15. Among them, the following conditions are also preferably satisfied: 3< (Ct1+Ct2+Ct3)/(T12+T23) <13. Among them, the following conditions are also preferably satisfied: 3.5< (Ct1+Ct2+Ct3)/(T12+T23) <13. Referring to fig. 19, a schematic diagram of parameters CT1, CT2, CT3, T12 and T23 according to a first embodiment of the present application is shown.

The first optical lens has a center thickness of CT1 on the optical axis, the second optical lens has a center thickness of CT2 on the optical axis, the third optical lens has a center thickness of CT3 on the optical axis, and the distance from the aperture to the image plane on the optical axis is SL, which preferably satisfies the following conditions: 0.20< (CT1+CT2+CT3)/SL <1.00. Thereby contributing to shortening the length of the optical system. Among them, the following conditions are also preferably satisfied: 0.30< (CT1+CT2+CT3)/SL <0.80. Among them, the following conditions are also preferably satisfied: 0.35< (CT1+CT2+CT3)/SL <0.60.

The present application provides a headset preferably comprising the aforementioned optical system. Preferably, the headset may further comprise a display, a digital signal processor, an inertial measurement unit, and a support structure. Preferably, the display is configured to face the eyes of the user to display the image, the digital signal processor is communicatively connected to the display and the inertial measurement unit, and the support structure is configured to be worn on the head of the user. Preferably, the optical system is available to the eyes of the user. In some embodiments, the headset may preferably include two of the aforementioned optical systems, and the two optical systems may be used by the user with both eyes, respectively.

Preferably, the headset may further comprise an iris recognition module, wherein the iris recognition module is communicatively connected to the digital signal processor, and the iris recognition module is configured to recognize the iris of the user. Therefore, the convenience and the safety of the user in the authentication system can be provided.

Preferably, the display may be an Organic Light-Emitting Diode (OLED) panel and have a Color Filter. Therefore, the organic light-emitting diode panel can provide better color images. Preferably, the organic light emitting diode panel filters with color filters, and a polarizing element may be included inside the organic light emitting diode panel to polarize light. Preferably, the organic light emitting diode panel may be, for example, a Micro light emitting diode (Micro LED) panel or a sub-millimeter light emitting diode (Mini LED) panel.

Preferably, the headset may further comprise a folding mechanism, wherein the folding mechanism is configured to cause the volume of the headset to be compressed. For example, the folding mechanism provides that the user can compress the volume of the headset (e.g., can fold the headset) without using the headset.

Preferably, the head-mounted device may further comprise an auto-focusing device, wherein the auto-focusing device is disposed corresponding to the optical system, and the auto-focusing device is used for moving an optical lens of the optical system. Therefore, the automatic focusing device can provide the focusing function of the optical system and can adjust the focal length according to different user eyesight. In some embodiments, the number of optical systems is two, and the number of autofocus devices is one, wherein the autofocus devices can adjust the focal lengths of the two optical systems simultaneously. In addition, in some embodiments, the number of the optical systems is two, and the number of the auto-focusing devices is two to adjust the focal lengths of the two optical systems respectively.

Preferably, the headset further comprises a camera, wherein the camera is in communication connection with the digital signal processor, and the camera has the function of capturing images of the external environment and presenting the images on the display. Therefore, the external environment image shot by the camera can be immediately presented on the display, so that a user can recognize the environment under the condition of wearing the head-mounted device.

Preferably, the head-mounted device may further comprise an eye tracking device, wherein the eye tracking device faces the eyes of the user to track the position of the eyes of the user. Therefore, the user can perform data analysis on the use condition (such as fixation target analysis or concentration analysis when the user plays games or watches videos), and the definition of each position of the picture can be adjusted according to the eyeball fixation range.

It is noted that the communication connection mentioned herein refers to a connection manner in which two elements exchange signals with each other, for example, by wired or wireless transmission.

The technical features in the optical system and the head-mounted device can be combined and configured to achieve corresponding effects.

In the optical system disclosed in the present application, the optical lens may be made of glass or plastic. If the optical lens is made of glass, the flexibility of the refractive power configuration of the optical system can be increased, and the influence of the external environmental temperature change on imaging can be reduced, and the glass lens can be manufactured by using polishing or molding technology. If the optical lens is made of plastic, the production cost can be effectively reduced. In addition, a spherical or Aspherical Surface (ASP) can be disposed on the mirror surface, wherein the spherical optical lens can reduce the manufacturing difficulty, and if the aspherical surface is disposed on the mirror surface, more control variables can be obtained, so as to reduce the aberration and the number of lenses, and effectively reduce the total length of the optical system. Further, the aspherical surface may be manufactured by plastic injection molding or molding a glass lens, etc.

In the optical system disclosed in the present application, if the optical lens surface is aspheric, it means that all or a part of the optically effective area of the optical lens surface is aspheric.

In the optical system disclosed by the application, additives can be selectively added into any one (above) optical lens material to generate a light absorption or light interference effect so as to change the transmissivity of the optical lens to light rays with specific wave bands and further reduce stray light and color cast. For example: the additive can have the function of filtering light rays in 600-800 nm wave bands in the system, so as to help reduce redundant red light or infrared light; or the light in the wave band of 350 nanometers to 450 nanometers can be filtered to reduce redundant blue light or ultraviolet light, so that the additive can avoid the interference of the light in the specific wave band on imaging. In addition, the additive can be uniformly mixed in plastics and manufactured into an optical lens by injection molding technology. In addition, the additive can be configured on the coating film on the surface of the optical lens to provide the effects.

In the optical system disclosed in the present application, if the optical lens surface is a convex surface and the convex position is not defined, it means that the convex surface may be located at the paraxial region of the optical lens surface; if the optical lens surface is concave and the concave position is not defined, it means that the concave surface may be located at the paraxial region of the optical lens surface. If the refractive power or focal length of the optical lens element does not define the position of the region, it means that the refractive power or focal length of the optical lens element can be the refractive power or focal length of the optical lens element at the paraxial region.

In the optical system disclosed in the present application, the Inflection Point (Point) of the optical lens refers to an intersection Point where the curvature of the surface of the optical lens changes positively and negatively.

In the optical system disclosed in the present application, the image surface of the optical system may be a plane or a curved surface with any curvature, particularly a curved surface with a concave surface facing the front side direction, according to the display corresponding to the image surface.

In the optical system disclosed in the present application, more than one imaging correction element (flat field element, etc.) can be selectively disposed between the optical lens closest to the image plane and the image plane on the imaging optical path, so as to achieve the effect of correcting the image (such as bending, etc.). The optical properties of the imaging modifying element, such as curvature, thickness, refractive index, position, surface (convex or concave, spherical or aspherical, diffractive, fresnel, etc.), can be adjusted to suit the headset requirements. Generally, the imaging correction device is preferably configured such that a thin plano-concave device having a concave surface facing the front side is disposed near the image surface.

In the optical system disclosed in the present application, at least one aperture may be disposed before the first optical lens, between the optical lenses or after the last optical lens, and the aperture may be a flare aperture (Glare Stop) or a Field aperture (Field Stop), so as to reduce stray light and help to improve image quality.

The application can be provided with a variable aperture element which can be a mechanical component or a light ray regulating element, and the size and shape of the aperture can be controlled by electric or electric signals. The mechanical member may include a movable member such as a vane group, a shield plate, or the like; the light modulating element may comprise a light filtering element, electrochromic material, liquid crystal layer, etc. shielding material. The variable aperture element can enhance the image adjusting capability by controlling the light incoming amount or the exposure time of the image. In addition, the variable aperture element can also be an aperture of the application, and the image quality, such as depth of field or exposure speed, can be adjusted by changing the aperture value.

One or more optical elements, which may be filters, polarizers, etc., but not the present application, may be appropriately placed to limit the passage of light through the optical system. Also, the optical element may be a monolithic element, a composite component, or presented as a film, etc., but this is not the case in the present application. The optical element can be arranged at the front end, the rear end or between the optical lenses of the optical system so as to control the light rays in a specific form to pass through and further meet the application requirements.

In accordance with the above embodiments, specific examples are set forth below in conjunction with the drawings.

< first embodiment >

Referring to fig. 1 to 3, fig. 1 is a schematic diagram of an optical system and a display according to a first embodiment of the present application, fig. 2 is an enlarged schematic diagram of a region EL1 in fig. 1, and fig. 3 is a schematic diagram of an aperture, a first optical lens, a second optical lens, a third optical lens, and an image plane of the optical system in fig. 1 and an imaging ray trace of different fields of view. The optical system 1 sequentially comprises an aperture ST, a first optical lens E1, a reflective polarizer RP, a first quarter-wave plate QWP1, a second optical lens E2, a third optical lens E3, a partial reflector BS, a second quarter-wave plate QWP2 and an image plane IMG from front side to rear side. The display SC is disposed on the image plane IMG. The optical system 1 includes three optical lenses (E1, E2, E3), and there are no other optical lenses interposed between the three optical lenses.

The first optical lens element E1 with negative refractive power has a concave front surface and a convex rear surface, and has aspheric surfaces and at least one inflection point.

The second optical lens element E2 with positive refractive power has a planar front surface and a convex rear surface, and is made of plastic material.

The third optical lens element E3 with positive refractive power has a concave front surface and a convex rear surface, and is made of plastic material.

As shown in fig. 2, the reflective polarizing element RP is attached to the rear side surface of the first optical lens E1, and the first quarter-wave plate QWP1 is attached to the side of the reflective polarizing element RP away from the first optical lens E1.

The partially reflecting element BS is attached to the rear side surface of the third optical lens E3.

The second quarter wave plate QWP2 is located between the partially reflective element BS and the image plane IMG.

The image light emitted from the display SC on the image plane IMG sequentially passes through the second quarter-wave plate QWP2, the partial reflection element BS, the first quarter-wave plate QWP1 and the reflection polarization element RP. Further, the imaging light with the longitudinal polarization state is emitted from the image plane IMG, forms a rotation polarization state through the second quarter-wave plate QWP2, forms a transverse polarization state through the partial reflection element BS, the third optical lens E3 and the second optical lens E2, then penetrates the first quarter-wave plate QWP1 again through reflection of the reflective polarization element RP, and then forms a rotation polarization state, and the imaging light with the rotation polarization state is reflected through the second optical lens E2 and the third optical lens E3 and through the partial reflection element BS, then passes through the third optical lens E3 and the second optical lens E2 again and penetrates the first quarter-wave plate QWP1 for the third time to form a longitudinal polarization state and then sequentially passes through the first optical lens E1 and the aperture ST, for example, to reach the eye position EYP of the user.

The curve equation of the aspherical surface of each optical lens is expressed as follows:

x: the displacement of the intersection point of the aspheric surface and the optical axis to the point on the aspheric surface, which is a distance Y from the optical axis, parallel to the optical axis;

y: the perpendicular distance of the point on the aspherical curve from the optical axis;

r: radius of curvature;

k: conical surface coefficient; and

ai: the i-th order aspheric coefficient.

In the optical system 1 of the first embodiment, the focal length of the optical system 1 is F, the aperture value (F-number) of the optical system 1 is Fno, and half of the maximum viewing angle in the optical system 1 is HFOV, which has the following values: f=21.31 millimeters (mm), fno=3.55, hfov=50.0 degrees (deg.).

The distance from the aperture ST to the front side surface of the first optical lens E1 on the optical axis is ER, which satisfies the following condition: er=12.00 mm.

The size of the aperture ST is EPD, which satisfies the following condition: epd=6.00 millimeters.

The image height presented by the image plane IMG is ImgH, which satisfies the following conditions: imgh=19.20 mm.

The focal length of the first optical lens E1 is f1, which satisfies the following condition: f1 -67.56 mm.

The focal length of the second optical lens E2 is f2, which satisfies the following condition: f2 = 151.24 mm.

The focal length of the third optical lens E3 is f3, which satisfies the following condition: f3 = 224.72 mm.

The radius of curvature of the front side surface of the third optical lens E3 is R5, and the radius of curvature of the rear side surface of the third optical lens E3 is R6, which satisfies the following condition: r6/r5=0.59.

The radius of curvature of the front side surface of the first optical lens E1 is R1, and the radius of curvature of the rear side surface of the first optical lens E1 is R2, which satisfies the following condition: r2/r1|=2.78.

The focal length of the optical system 1 is f, and the focal length of the first optical lens E1 is f1, which satisfies the following condition: f/f1= -0.32.

The focal length of the optical system 1 is f, and the focal length of the second optical lens E2 is f2, which satisfies the following condition: ff2=0.14.

The focal length of the optical system 1 is f, and the focal length of the third optical lens E3 is f3, which satisfies the following condition: ff3=0.09.

The abbe number of the first optical lens E1 is V1, and the refractive index of the first optical lens E1 is N1, which satisfies the following condition: v1/n1=13.03.

The abbe number of the second optical lens E2 is V2, and the refractive index of the second optical lens E2 is N2, which satisfies the following condition: v2/n2=38.42.

The abbe number of the third optical lens E3 is V3, and the refractive index of the third optical lens E3 is N3, which satisfies the following condition: v3/n3=38.42.

The focal length of the optical system 1 is f, and the image height represented by the image plane IMG is ImgH, which satisfies the following conditions: f/imgh=1.11.

The distance between the aperture ST and the image plane IMG on the optical axis is SL, and the image height represented by the image plane IMG is ImgH, which satisfies the following conditions: SL/imgh=1.61.

The distance between the aperture ST and the image plane IMG on the optical axis is SL, and the focal length of the optical system 1 is f, which satisfies the following conditions: SL/f=1.46.

The size of the aperture ST is EPD, and the image height presented by the image plane IMG is ImgH, which satisfies the following conditions: EPD/imgh=0.31.

Half of the maximum viewing angle in the optical system 1 is HFOV and the focal length of the optical system 1 is f, which satisfies the following condition: tan (HFOV)/f=0.06.

The distance from the aperture ST to the front surface of the first optical lens E1 on the optical axis is ER, and the distance from the aperture ST to the image plane IMG on the optical axis is SL, which satisfies the following condition: ER/sl=0.39.

The distance between the front surface of the first optical lens E1 and the rear surface of the third optical lens E3 on the optical axis is TD, and the distance between the aperture ST and the image plane IMG on the optical axis is SL, which satisfies the following conditions: TD/sl=0.52.

The first optical lens E1 has a center thickness on the optical axis of CT1, the second optical lens E2 has a center thickness on the optical axis of CT2, the third optical lens E3 has a center thickness on the optical axis of CT3, the distance from the rear surface of the first optical lens E1 to the front surface of the second optical lens E2 on the optical axis is T12, and the distance from the rear surface of the second optical lens E2 to the front surface of the third optical lens E3 on the optical axis is T23, which satisfies the following conditions: (ct1+ct2+ct3)/(t12+t23) =3.82.

The first optical lens element E1 has a central thickness of CT1 on the optical axis, the second optical lens element E2 has a central thickness of CT2 on the optical axis, the third optical lens element E3 has a central thickness of CT3 on the optical axis, and the distance from the aperture ST to the image plane IMG on the optical axis is SL, which satisfies the following conditions: (CT 1+ CT2+ CT 3)/sl=0.41.

The distance on the optical axis from the rear surface of the first optical lens E1 to the front surface of the second optical lens E2 is T12, the distance on the optical axis from the rear surface of the second optical lens E2 to the front surface of the third optical lens E3 is T23, and the distance on the optical axis from the front surface of the first optical lens E1 to the rear surface of the third optical lens E3 is TD, which satisfies the following conditions: (t12+t23)/td=0.21.

The radius of curvature of the front side surface of the first optical lens E1 is R1, and the radius of curvature of the rear side surface of the third optical lens E3 is R6, which satisfies the following condition: r1/r6=0.59.

The radius of curvature of the front side surface of the first optical lens E1 is R1, and the radius of curvature of the rear side surface of the first optical lens E1 is R2, which satisfies the following condition: (r1+r2)/(r1—r2) = -2.12.

The radius of curvature of the front side surface of the third optical lens E3 is R5, and the radius of curvature of the rear side surface of the third optical lens E3 is R6, which satisfies the following condition: (r5+r6)/(R5-R6) =3.92.

Please refer to the following table 1A and table 1B.

Table 1A discloses only the structural data of the first optical lens E1, the second optical lens E2 and the third optical lens E3 in the optical system 1 according to the first embodiment, wherein the unit of curvature radius and thickness is millimeter (mm), and the surfaces 16 to 0 respectively represent the surfaces through which the imaging light sequentially passes from the image plane IMG to the position EYP of the eyes of the user. It should be understood that each element in the optical system 1 may have a thickness, but for clarity and brevity in disclosure of the optical characteristics of the optical lenses in the optical system 1, the structural data of the second quarter-wave plate QWP2, the partially reflective element BS, the first quarter-wave plate QWP1 and the reflective polarizing element RP are omitted in table 1A.

Table 1B shows aspherical data in the first embodiment, where k is a conic coefficient in an aspherical curve equation, and A4 to a12 represent aspherical coefficients of 4 th to 12 th order of each surface.

The following tables of the embodiments are schematic diagrams corresponding to the embodiments, and the definition of data in the tables is the same as that of tables 1A and 1B of the first embodiment, and is not repeated herein.

< second embodiment >

Fig. 4 is a schematic diagram showing an optical system and a display according to a second embodiment of the present application. The optical system 2 sequentially includes, from the front side to the rear side, an aperture ST, a first optical lens E1, a reflective polarizer (not shown), a first quarter-wave plate (not shown), a second optical lens E2, a third optical lens E3, a partially reflective polarizer (not shown), a second quarter-wave plate (not shown), and an image plane IMG. The display SC is disposed on the image plane IMG. The optical system 2 includes three optical lenses (E1, E2, E3), and there are no other optical lenses interposed between the three optical lenses. The reflective polarizing element, the first quarter-wave plate, the partially reflective element, and the second quarter-wave plate of the optical system 2 of the present embodiment have the same or similar structural features as those of the optical system 1 of the first embodiment, so these elements are not shown in fig. 4 for clarity and brevity.

The third optical lens element E3 with negative refractive power has a concave front surface and a convex rear surface, and is made of plastic material.

The reflective polarizing element is attached to the rear side surface of the first optical lens E1, and the first quarter-wave plate is attached to the side of the reflective polarizing element remote from the first optical lens E1.

A partially reflecting element is attached to the rear side surface of the third optical lens E3.

The second quarter-wave plate is located between the partially reflective element and the image plane IMG.

The imaging light emitted from the display SC on the image plane IMG sequentially passes through the second quarter-wave plate, the partial reflection element, the first quarter-wave plate and the reflection polarization element. Further, the imaging light in the longitudinal polarization state is emitted from the image plane IMG, forms a rotation polarization state through the second quarter-wave plate, passes through the partial reflection element, the third optical lens E3 and the second optical lens E2, then passes through the first quarter-wave plate, forms a transverse polarization state, then passes through the first quarter-wave plate again through reflection of the reflection polarization element, forms a rotation polarization state, then passes through the second optical lens E2 and the third optical lens E3, and is reflected by the partial reflection element, then passes through the third optical lens E3 and the second optical lens E2 again and passes through the first quarter-wave plate for the third time, forms a longitudinal polarization state, and then passes through the first optical lens E1 and the aperture ST sequentially, for example, to reach a position EYP of the user's eye.

Please refer to the following table 2A and table 2B.

In the second embodiment, the curve equation of the aspherical surface represents the form as in the first embodiment. In addition, the following are listed

The definitions in table 2C are the same as those in the first embodiment, and are not repeated here.

< third embodiment >

Fig. 5 is a schematic diagram showing an optical system and a display according to a third embodiment of the present application. The optical system 3 sequentially includes, from the front side to the rear side, an aperture ST, a first optical lens E1, a reflective polarizer (not shown), a first quarter-wave plate (not shown), a second optical lens E2, a third optical lens E3, a partially reflective polarizer (not shown), a second quarter-wave plate (not shown), and an image plane IMG. The display SC is disposed on the image plane IMG. The optical system 3 includes three optical lenses (E1, E2, E3), and there are no other optical lenses interposed between the three optical lenses. The reflective polarizing element, the first quarter-wave plate, the partially reflective element, and the second quarter-wave plate of the optical system 3 of the present embodiment have the same or similar structural features as those of the optical system 1 of the first embodiment, so these elements are not shown in fig. 5 for clarity and brevity.

Please refer to the following tables 3A and 3B.

In a third embodiment, the curve equation for the aspherical surface represents the form as in the first embodiment. In addition, the following are listed

The definitions in table 3C are the same as those in the first embodiment, and are not repeated here.

< fourth embodiment >

Fig. 6 is a schematic diagram showing an optical system and a display according to a fourth embodiment of the present application. The optical system 4 sequentially includes, from the front side to the rear side, an aperture ST, a first optical lens E1, a reflective polarizer (not shown), a first quarter-wave plate (not shown), a second optical lens E2, a third optical lens E3, a partially reflective polarizer (not shown), a second quarter-wave plate (not shown), and an image plane IMG. The display SC is disposed on the image plane IMG. The optical system 4 includes three optical lenses (E1, E2, E3), and there are no other optical lenses interposed between the three optical lenses. The reflective polarizing element, the first quarter-wave plate, the partially reflective element, and the second quarter-wave plate of the optical system 4 of the present embodiment have the same or similar structural features as those of the optical system 1 of the first embodiment, so these elements are not shown in fig. 6 for clarity and brevity.

Please refer to the following tables 4A and 4B.

In the fourth embodiment, the curve equation of the aspherical surface represents the form as in the first embodiment. In addition, the following are listed

The definitions in table 4C are the same as those in the first embodiment, and are not repeated here.

< fifth embodiment >

Fig. 7 is a schematic diagram showing an optical system and a display according to a fifth embodiment of the present application. The optical system 5 sequentially includes, from the front side to the rear side, an aperture ST, a first optical lens E1, a reflective polarizer (not shown), a first quarter-wave plate (not shown), a second optical lens E2, a third optical lens E3, a partially reflective polarizer (not shown), a second quarter-wave plate (not shown), and an image plane IMG. The display SC is disposed on the image plane IMG. The optical system 5 includes three optical lenses (E1, E2, E3), and there are no other optical lenses interposed between the three optical lenses. The reflective polarizing element, the first quarter-wave plate, the partially reflective element, and the second quarter-wave plate of the optical system 5 of the present embodiment have the same or similar structural features as those of the optical system 1 of the first embodiment, so these elements are not shown in fig. 7 for clarity and brevity.

Please refer to the following table 5A and table 5B.

In the fifth embodiment, the curve equation of the aspherical surface represents the form as in the first embodiment. In addition, the following are listed

The definitions in table 5C are the same as those in the first embodiment, and are not repeated here.

< sixth embodiment >

Fig. 8 is a schematic diagram showing an optical system and a display according to a sixth embodiment of the present application. The optical system 6 sequentially includes, from the front side to the rear side, an aperture ST, a first optical lens E1, a reflective polarizer (not shown), a first quarter-wave plate (not shown), a second optical lens E2, a third optical lens E3, a partially reflective polarizer (not shown), a second quarter-wave plate (not shown), and an image plane IMG. The display SC is disposed on the image plane IMG. The optical system 6 includes three optical lenses (E1, E2, E3), and there are no other optical lenses interposed between the three optical lenses. The reflective polarizing element, the first quarter-wave plate, the partially reflective element, and the second quarter-wave plate of the optical system 6 of the present embodiment have the same or similar structural features as those of the optical system 1 of the first embodiment, so these elements are not shown in fig. 8 for clarity and brevity.

The second optical lens element E2 with negative refractive power has a planar front surface and a concave rear surface, and is made of plastic material.

Please refer to the following table 6A and table 6B.

In the sixth embodiment, the curve equation of the aspherical surface represents the form as in the first embodiment. In addition, the following are listed

The definitions in table 6C are the same as those in the first embodiment, and are not repeated here.

< seventh embodiment >

Fig. 9 is a schematic diagram showing an optical system and a display according to a seventh embodiment of the present application. The optical system 7 sequentially includes, from the front side to the rear side, an aperture ST, a first optical lens E1, a reflective polarizer (not shown), a first quarter-wave plate (not shown), a second optical lens E2, a third optical lens E3, a partially reflective polarizer (not shown), a second quarter-wave plate (not shown), and an image plane IMG. The display SC is disposed on the image plane IMG. The optical system 7 includes three optical lenses (E1, E2, E3), and there are no other optical lenses interposed between the three optical lenses. The reflective polarizing element, the first quarter-wave plate, the partially reflective element, and the second quarter-wave plate of the optical system 7 of the present embodiment have the same or similar structural features as those of the optical system 1 of the first embodiment, so these elements are not shown in fig. 9 for clarity and brevity.

Please refer to the following table 7A and table 7B.

In the seventh embodiment, the curve equation of the aspherical surface represents the form as in the first embodiment. In addition, the following are listed

The definitions in table 7C are the same as those in the first embodiment, and are not repeated here.

< eighth embodiment >

Fig. 10 is a schematic diagram showing an optical system and a display according to an eighth embodiment of the present application. The optical system 8 sequentially includes, from the front side to the rear side, an aperture ST, a first optical lens E1, a reflective polarizer (not shown), a first quarter-wave plate (not shown), a second optical lens E2, a third optical lens E3, a partially reflective polarizer (not shown), a second quarter-wave plate (not shown), and an image plane IMG. The display SC is disposed on the image plane IMG. The optical system 8 includes three optical lenses (E1, E2, E3), and there are no other optical lenses interposed between the three optical lenses. The reflective polarizing element, the first quarter-wave plate, the partially reflective element, and the second quarter-wave plate of the optical system 8 of the present embodiment have the same or similar structural features as those of the optical system 1 of the first embodiment, so these elements are not shown in fig. 10 for clarity and brevity.

Please refer to the following tables 8A and 8B.

In the eighth embodiment, the curve equation of the aspherical surface represents the form as in the first embodiment. In addition, the following are listed

The definitions in table 8C are the same as those in the first embodiment, and are not repeated here.

< ninth embodiment >

Fig. 11 is a schematic diagram showing an optical system and a display according to a ninth embodiment of the present application. The optical system 9 sequentially includes, from the front side to the rear side, an aperture ST, a first optical lens E1, a reflective polarizer (not shown), a first quarter-wave plate (not shown), a second optical lens E2, a third optical lens E3, a partially reflective polarizer (not shown), a second quarter-wave plate (not shown), and an image plane IMG. The display SC is disposed on the image plane IMG. The optical system 9 includes three optical lenses (E1, E2, E3), and there are no other optical lenses interposed between the three optical lenses. The reflective polarizing element, the first quarter-wave plate, the partially reflective element, and the second quarter-wave plate of the optical system 9 of the present embodiment have the same or similar structural features as those of the optical system 1 of the first embodiment, so these elements are not shown in fig. 11 for clarity and brevity.

Please refer to the following table 9A and table 9B.

In the ninth embodiment, the curve equation of the aspherical surface represents the form as in the first embodiment. In addition, the following are listed

The definitions in table 9C are the same as those in the first embodiment, and are not repeated here.

/>

< tenth embodiment >

Fig. 12 is a schematic diagram showing an optical system and a display according to a tenth embodiment of the present application. The optical system 10 sequentially includes, from front side to rear side, an aperture ST, a first optical lens E1, a reflective polarizer (not shown), a first quarter-wave plate (not shown), a second optical lens E2, a third optical lens E3, a partially reflective polarizer (not shown), a second quarter-wave plate (not shown), and an image plane IMG. The display SC is disposed on the image plane IMG. The optical system 10 includes three optical lenses (E1, E2, E3) with no other intervening optical lenses between the three optical lenses. The reflective polarizing element, the first quarter-wave plate, the partially reflective element, and the second quarter-wave plate of the optical system 10 of the present embodiment have the same or similar structural features as those of the optical system 1 of the first embodiment, so these elements are not shown in fig. 12 for clarity and brevity.

Please refer to the following tables 10A and 10B.

In the tenth embodiment, the curve equation of the aspherical surface represents the form as in the first embodiment. In addition, the following are listed

The definition of table 10C is the same as that of the first embodiment, and will not be repeated here.

< eleventh embodiment >

Fig. 13 is a schematic diagram showing an optical system and a display according to an eleventh embodiment of the disclosure. The optical system 11 sequentially includes, from front side to rear side, an aperture ST, a first optical lens E1, a reflective polarizer (not shown), a first quarter-wave plate (not shown), a second optical lens E2, a third optical lens E3, a partially reflective polarizer (not shown), a second quarter-wave plate (not shown), and an image plane IMG. The display SC is disposed on the image plane IMG. The optical system 11 includes three optical lenses (E1, E2, E3), and there are no other optical lenses interposed between the three optical lenses. The reflective polarizing element, the first quarter-wave plate, the partially reflective element, and the second quarter-wave plate of the optical system 11 of the present embodiment have the same or similar structural features as those of the optical system 1 of the first embodiment, so these elements are not shown in fig. 13 for clarity and brevity.

Please refer to the following tables 11A and 11B.

In the eleventh embodiment, the curve equation of the aspherical surface represents the form as in the first embodiment. In addition, the definition of the following table 11C is the same as that of the first embodiment, and will not be repeated here.

< twelfth embodiment >

Fig. 14 is a schematic diagram showing an optical system and a display according to a twelfth embodiment of the present application. The optical system 12 sequentially includes, from front side to rear side, an aperture ST, a first optical lens E1, a reflective polarizer (not shown), a first quarter-wave plate (not shown), a second optical lens E2, a third optical lens E3, a partially reflective polarizer (not shown), a second quarter-wave plate (not shown), and an image plane IMG. The display SC is disposed on the image plane IMG. The optical system 12 includes three optical lenses (E1, E2, E3) with no other intervening optical lenses between the three optical lenses. The reflective polarizing element, the first quarter-wave plate, the partially reflective element, and the second quarter-wave plate of the optical system 12 of the present embodiment have the same or similar structural features as those of the optical system 1 of the first embodiment, so these elements are not shown in fig. 14 for clarity and brevity.

Please refer to the following tables 12A and 12B.

In the twelfth embodiment, the curve equation of the aspherical surface represents the form as in the first embodiment. In addition, the definition of the following table 12C is the same as that of the first embodiment, and will not be repeated here.

< thirteenth embodiment >

Fig. 15 is a schematic diagram showing an optical system and a display according to a thirteenth embodiment of the present application. The optical system 13 sequentially includes, from the front side to the rear side, an aperture ST, a first optical lens E1, a reflective polarizer (not shown), a first quarter-wave plate (not shown), a second optical lens E2, a third optical lens E3, a partially reflective polarizer (not shown), a second quarter-wave plate (not shown), and an image plane IMG. The display SC is disposed on the image plane IMG. The optical system 13 includes three optical lenses (E1, E2, E3), and there are no other optical lenses interposed between the three optical lenses. The reflective polarizing element, the first quarter-wave plate, the partially reflective element, and the second quarter-wave plate of the optical system 13 of the present embodiment have the same or similar structural features as those of the optical system 1 of the first embodiment, so these elements are not shown in fig. 15 for clarity and brevity.

The first optical lens element E1 with negative refractive power has a concave front surface and a convex rear surface, and is made of plastic material.

Please refer to the following tables 13A and 13B.

In the thirteenth embodiment, the curve equation of the aspherical surface represents the form as in the first embodiment. In addition, the definition of the following table 13C is the same as that of the first embodiment, and will not be repeated here.

< fourteenth embodiment >

Fig. 16 is a schematic diagram showing an optical system and a display according to a fourteenth embodiment of the present application. The optical system 14 sequentially includes, from front side to rear side, an aperture ST, a first optical lens E1, a reflective polarizer (not shown), a first quarter-wave plate (not shown), a second optical lens E2, a third optical lens E3, a partially reflective polarizer (not shown), a second quarter-wave plate (not shown), and an image plane IMG. The display SC is disposed on the image plane IMG. The optical system 14 includes three optical lenses (E1, E2, E3), and there are no other optical lenses interposed between the three optical lenses. The reflective polarizing element, the first quarter-wave plate, the partially reflective element, and the second quarter-wave plate of the optical system 14 of the present embodiment have the same or similar structural features as those of the optical system 1 of the first embodiment, so these elements are not shown in fig. 16 for clarity and brevity.

Please refer to the following tables 14A and 14B.

In the fourteenth embodiment, the curve equation of the aspherical surface represents the form as in the first embodiment. In addition, the definition of the following table 14C is the same as that of the first embodiment, and will not be described herein.

< fifteenth embodiment >

Referring to fig. 17 and 18, fig. 17 is a schematic diagram of a headset according to a fifteenth embodiment of the present application, and fig. 18 is a schematic diagram of a top view of the headset of fig. 17.

The headset 10 of the present embodiment can be applied to AR, VR, MR or projection glasses, which includes a display 101, a digital signal processor 102, an inertial measurement unit 103, a support structure 104, an eye tracking device 105, two optical systems 106, two autofocus devices 107, two cameras 108, a folding mechanism 109, and an iris recognition module 100. The optical system 106 may be any of the optical systems of the foregoing embodiments, which is not limited to the above embodiments.

The display 101 is configured to face the eyes of the user to display an image. The inertial measurement unit 103 is configured to measure angular velocity and acceleration of the headset 10 in three-dimensional space to derive a posture of the headset 10. The support structure 104 may be at least one strap or at least one glasses-like temple structure for wearing on the head of a user. The eye tracking device 105 is used for facing the eyes of the user to track the gazing position of the eyes of the user, so that the user can perform data analysis on the use condition, and the definition of each position of the picture can be adjusted according to the eye gazing range. The two sets of optical systems 106 are respectively available to the user for use with both eyes. The two sets of auto-focusing devices 107 are respectively disposed corresponding to the two sets of optical systems 106, and the auto-focusing devices 107 are used for moving the optical lenses of the optical systems 106, so as to provide the focusing function of the optical systems 106, and adjust the focal length for different user's eyesight. The camera 108 and the display 101 are respectively connected to the digital signal processor 102 in a communication manner, and the camera 108 can capture images of the external environment and present the images on the display 101 through the digital signal processor 102. The external environment image captured by the camera 108 can be displayed on the display 101 in real time, so that the user can recognize the environment while wearing the headset 10. Therefore, through the camera configuration, the capturing and real-time displaying of the external environment image can be utilized to provide the functions of the head-mounted device VR mode, the AR mode, the MR mode and the like, and the external image real-time displaying function can be used for watching the surrounding environment without taking off the head-mounted device 10. In addition, by the arrangement of at least two cameras, the optical zoom of the multi-lens arrangement can be provided, or the identification function can be provided by using computer vision. Among other things, multi-camera configurations may include a class of light arrival module configurations, such as structured light or Time of Flight ranging (Flight), to provide more diverse functionality. The folding mechanism 109 provides a user with the ability to compress the volume of the headgear 10, such as to fold the headgear 10, without the need to use the headgear 10. The iris recognition module 100 is communicatively connected to the digital signal processor 102, and the iris recognition module 100 is used for recognizing the iris of the user.

In some embodiments, the headset may also have bluetooth or wireless network functionality to allow communication with at least one external device.

In some embodiments, the headset may also have at least one speaker, at least one earphone, or at least one noise reduction earphone to provide the user with sound. In some embodiments, the headset may also have at least one microphone to receive the sound of the user.

In some embodiments, the headset may be associated with at least one controller, wherein the controller may be a joystick, a handle, or a hand-held device, so as to provide the user with interaction functions such as VR mode, AR mode, MR mode, etc. of the headset.

While the present application is disclosed in the foregoing embodiments, the embodiments are not intended to limit the present application. All changes and modifications that come within the spirit and scope of the invention are desired to be protected by the following claims. Reference is made to the appended claims for a review of the scope of the protection defined herein.

Claims

1. An optical system, comprising:

an aperture positioned on the front side of the optical system;

an image surface positioned at the rear side of the optical system;

A reflective polarizing element located between the aperture and the image surface;

a part of reflection element, which is positioned between the reflection type polarized light element and the image surface;

a first quarter-wave plate located between the reflective polarizing element and the partially reflective element;

a second quarter wave plate located between the partial reflection element and the image surface;

a first optical lens located between the aperture and the image surface;

a second optical lens located between the first optical lens and the image surface; and

a third optical lens located between the second optical lens and the image surface;

wherein the first optical lens has negative refractive power, the third optical lens has positive refractive power, and the front side surface of the second optical lens is a plane;

wherein the radius of curvature of the front side surface of the third optical lens is R5, and the radius of curvature of the rear side surface of the third optical lens is R6, which satisfies the following condition:

0.13<R6/R5。

2. the optical system of claim 1, wherein the radius of curvature of the front surface of the third optical lens is R5 and the radius of curvature of the back surface of the third optical lens is R6, which satisfies the following condition:

0.15<R6/R5。

3. The optical system of claim 1, wherein at least one optical lens in the optical system has a inflection point.

4. An optical system according to claim 3, wherein the first optical lens rear surface has at least one inflection point.

5. The optical system of claim 1, wherein the first optical lens has an abbe number V1, the second optical lens has an abbe number V2, the third optical lens has an abbe number V3, the i-th optical lens has an abbe number Vi, the first optical lens has a refractive index N1, the second optical lens has a refractive index N2, the third optical lens has a refractive index N3, the i-th optical lens has a refractive index Ni, and at least one optical lens in the optical system satisfies the following condition:

10< vi/Ni <50, where i=1, 2 or 3.

6. The optical system of claim 1, wherein the focal length of the optical system is f, and the image plane presents an image height of ImgH, which satisfies the following condition:

1.00<f/ImgH<1.50。

7. the optical system according to claim 1, wherein the distance on the optical axis from the aperture to the image surface is SL, and the image surface exhibits an image height of ImgH, which satisfies the following condition:

1.2<SL/ImgH<2.0。

8. The optical system according to claim 1, wherein a distance on an optical axis from the aperture to the image surface is SL, and a focal length of the optical system is f, which satisfies the following condition:

1.2<SL/f<2.0。

9. the optical system according to claim 1, wherein a distance on the optical axis from the aperture to the front side surface of the first optical lens is ER, and a distance on the optical axis from the aperture to the image surface is SL, which satisfies the following condition:

0.30<ER/SL<0.50。

10. the optical system according to claim 1, wherein a distance on the optical axis from the front side surface of the first optical lens to the rear side surface of the third optical lens is TD, and a distance on the optical axis from the aperture to the image surface is SL, which satisfies the following condition:

0.40<TD/SL<0.60。

11. the optical system of claim 1, wherein the first optical lens has a center thickness on the optical axis of CT1, the second optical lens has a center thickness on the optical axis of CT2, the third optical lens has a center thickness on the optical axis of CT3, the first optical lens rear surface has a distance on the optical axis of T12 from the second optical lens front surface, and the second optical lens rear surface has a distance on the optical axis of T23 from the third optical lens front surface, satisfying the following condition:

1<(CT1+CT2+CT3)/(T12+T23)<20。

12. The optical system of claim 1, wherein the first optical lens has a central thickness on the optical axis of CT1, the second optical lens has a central thickness on the optical axis of CT2, the third optical lens has a central thickness on the optical axis of CT3, and the distance from the aperture to the image plane on the optical axis is SL, which satisfies the following condition:

0.20<(CT1+CT2+CT3)/SL<1.00。

13. the optical system of claim 1, wherein the image plane emits an imaging light, and the imaging light passes through the second quarter-wave plate, the partially reflective element, the first quarter-wave plate, and the reflective polarizing element in order.

14. A headset, comprising:

the optical system of claim 1.

15. An optical system, comprising:

an aperture positioned on the front side of the optical system;

an image surface positioned at the rear side of the optical system;

a first optical lens located between the aperture and the image surface;

wherein the first optical lens has negative refractive power and the front side surface of the second optical lens is a plane;

wherein the radius of curvature of the front side surface of the first optical lens is R1, and the radius of curvature of the rear side surface of the first optical lens is R2, which satisfies the following condition:

|R2/R1|<1000。

16. the optical system of claim 15, wherein the radius of curvature of the first optical lens front side surface is R1 and the radius of curvature of the first optical lens rear side surface is R2, which satisfies the following condition:

|R2/R1|<500。

17. the optical system of claim 15, wherein at least one optical lens in the optical system has a inflection point.

18. The optical system of claim 17, wherein the first optical lens backside surface has at least one inflection point.

19. The optical system of claim 15, wherein the first optical lens has an abbe number V1, the second optical lens has an abbe number V2, the third optical lens has an abbe number V3, the i-th optical lens has an abbe number Vi, the first optical lens has a refractive index N1, the second optical lens has a refractive index N2, the third optical lens has a refractive index N3, the i-th optical lens has a refractive index Ni, and at least one optical lens in the optical system satisfies the following condition:

10< vi/Ni <50, where i=1, 2 or 3.

20. The optical system of claim 15, wherein the focal length of the optical system is f, and the image plane presents an image height of ImgH, which satisfies the following condition:

1.00<f/ImgH<1.50。

21. the optical system of claim 15, wherein the distance between the aperture and the image surface on the optical axis is SL, and the image surface presents an image height of ImgH, which satisfies the following condition:

1.2<SL/ImgH<2.0。

22. the optical system of claim 15, wherein the distance between the aperture and the image surface on the optical axis is SL, and the focal length of the optical system is f, which satisfies the following condition:

1.2<SL/f<2.0。

23. The optical system according to claim 15, wherein a distance on the optical axis from the aperture to the front side surface of the first optical lens is ER, and a distance on the optical axis from the aperture to the image surface is SL, which satisfies the following condition:

0.30<ER/SL<0.50。

24. the optical system of claim 15, wherein a distance on the optical axis from the front surface of the first optical lens to the rear surface of the third optical lens is TD, and a distance on the optical axis from the aperture to the image surface is SL, which satisfies the following condition:

0.40<TD/SL<0.60。

25. the optical system of claim 15, wherein the first optical lens has a center thickness on the optical axis of CT1, the second optical lens has a center thickness on the optical axis of CT2, the third optical lens has a center thickness on the optical axis of CT3, the first optical lens rear surface has a distance on the optical axis of T12 from the second optical lens front surface, and the second optical lens rear surface has a distance on the optical axis of T23 from the third optical lens front surface, satisfying the following condition:

1<(CT1+CT2+CT3)/(T12+T23)<20。

26. the optical system of claim 15, wherein the first optical lens has a central thickness on the optical axis of CT1, the second optical lens has a central thickness on the optical axis of CT2, the third optical lens has a central thickness on the optical axis of CT3, and the distance from the aperture to the image plane on the optical axis is SL, which satisfies the following condition:

0.20<(CT1+CT2+CT3)/SL<1.00。

27. The optical system of claim 15, wherein the image plane emits an imaging light, and the imaging light passes through the second quarter-wave plate, the partially reflective element, the first quarter-wave plate, and the reflective polarizing element in order.

28. A headset, comprising:

the optical system of claim 15.